From my own experience WD40 is rubbish for drilling and taping, go and get yourself a tin of special grease (usualy about 10quid for a massive tin which will last for aaages ).
Tin is white with bright orange stripe somewhere. Can check it tomorrow if you want.
Does the job fine for me qbazdz & is also excellent for getting marker off the metal .
A bit that I think every diy modder fears getting wrong when making the mobo mounts is done & correct so with me not being a drinker or anything I'll post a load of pics instead lol .
So, I put the case on it's side with the io shield in.
Took my last pc & placed it in the case.
Held it up enough to have the io bits fit inside the shield & drawn along the edge & with the edge being drawn I could remove the io shield.
Then line the board up to the line & poke a marker through to get the exact mounting positions, then spot drilled, then drilled, then tried tapping but the tap fell straight through , so I either used the wrong drill bit or drilled it badly so I went back to the trusty brass inserts & made the hole 4mm & whacked them in .
Then put the standoffs in.
Tadaaa & wooooo hooooooo .
Now all I need to do is drill & file the expansion slots in the mobo panel.
Also I pre-drilled the positions for the fan mount bars.